Biological explanations for schizophrenia

SCHIZOPHRENIA BIOLOGICAL EXPLANATIONS- A01A01- The Genetic explanation of Schizophrenia proposes that thedisorder is hereditary ­ it runs in families.A01- family studies show that the risk of developing schizophrenia isgreater for those more closely related to the schizophrenic.A01-Kendler et al (1985) found that 1st degree relatives of thosewith schizophrenia are 18 times more at risk than the generalPopulationA01- Gottesman (1991) did a meta-analysis on 40 twin studies andfound that with MZ(identical) twins there was a 48% concordancerate but in DZ(non identical) twins there was a 17% concordancerate. A02- This shows a genetic link for Schizophrenia, if there wasno genetic factor then there should be no difference between MZand DZ twins. The fact that there's a difference suggests a geneticlink.A01- concordance rates are the chance that someone will develop adisorder if their related to someone who has it.A01- Sheilds (1962) found that MZ twins raised in different familiesstill showed around 50% concordance reinforces that genetics ismore significant than environment.A01- Torrey (1994) reviewed evidence from twin studies, findingthat if one MZ twins develops the condition there is a 28% chancethe other twin will suggesting genetics play a role in thedevelopment of schizophrenia.A01- Malaspina found that patients who have schizophrenia in theirfamily histories are more likely to develop negative symptoms thanthose families who are schizophrenia free.

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A01- Joseph who looked at nine of the most recent studiesconducted and found the concordance rate for MZ twins to be22.4% and for DZ 4.…read more

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A01- Post mortems and PET scans show that schizophrenics haveabnormally high levels of dopamine this supports the dopaminehypothesis.A01- Seeman (1987) found increases in dopamine receptor densityof between 60 ­ 110 % compared to controls.A01- PET scans ( live investigation of the brain) Wong et al ( 1986)found a 2-fold increase in density of dopamine receptor sites inschizophrenic patients who hadn't been treated withanti-psychotics.…read more

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A01- Young et al (1990) found a number o structural differences inMRI scans when comparing the brains of schizophrenic andnon-schizophrenic individuals this suggests that brain differencesare strongly linked with the development of schizophrenia.A01- Psychologists have reported that some schizophrenics havedifficult births which could have starved their brains of oxygen.A01- Chua & Mckenna (1995) found Enlarged ventricles, Smallercorpus collosum in schizophrenics suggesting brain abnormalitiesare linked with schizophrenia.…read more

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SCHIZOPHRENIA BILOGICAL EXPLANATIONS ­ A02/A03A02- If there was no genetic link then there should be no differencein the level of risk between first degree relatives and the public.A02- the fact that concordance rates increased with geneticrelatedness may be explained by the fact that families are likely tospend more time together which means environmental factors maybe influenced .…read more

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A02- Consistent evidence which makes it very reliableA02- Theory is based on nature alone so it is reductionist and highlydeterministic.A02- Family, twin and adoption studies must be consideredcautiously because they are retrospective and may be biased byknowledge that another family member has been diagnosed.A02- The sample size of twin, family and adoption studies tends tobe small so population validity may be low.A02- Even MZ twins reared apart share a womb so environmentalfactors cannot be discounted.…read more

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A02- One of the most commonly used theories because it can beproved empirically so it's more convincing.A02- Healy (2000) believes pharmaceutical companies were keen tosee the dopamine theory promoted because they would make hugeprofits from manufacturing anti-schizophrenic drugs that inhibiteddopamine production.A02- Brain abnormalities are not consistent amongst schizophrenicsso the Neuroanatomical approach is not reliable.…read more